分治算法经典案例 - 棋盘问题

/*
@theme:棋盘用L型的块堆满
@writer:pprp
@declare:最经典的分治算法
@date:2017/8/26
*/
#include <bits/stdc++.h>
#include <iostream>

using namespace std;
const int maxn = 10000;
int chess[maxn][maxn];
int number;

void chessBoard(int row, int column, int x, int y, int Size)
{
       if(Size == 1) return ;//退出条件
       int ss = Size/2;//分治，规模减半
       
       int t = ++number;
       int centerRow = row + ss;
       int centerColumn = column + ss;
       
       //开始判断四个方向
       //左上角判断
       if(x < centerRow && y < centerColumn)
       {
             chessBoard(row,column,x,y,ss);
       }
       else
       {
             chess[centerRow-1][centerColumn-1] = t;
             chessBoard(row,column,centerRow-1,centerColumn-1,ss);
       }
       
       //右上角判断
       if(x < centerRow && y >= centerColumn)
       {
             chessBoard(row,centerColumn,x,y,ss);
       }
       else
       {
             chess[centerRow-1][centerColumn] = t;
             chessBoard(row,centerColumn,centerRow-1,centerColumn,ss);
       }
       
       //左下角判断
       if(x >= centerRow && y < centerColumn)
       {
             chessBoard(centerRow,column,x,y,ss);
       }
       else
       {
             chess[centerRow][centerColumn-1] = t;
             chessBoard(centerRow,column,centerRow,centerColumn-1,ss);
       }                                                                   
       
       //右下角判断
       if(x >= centerRow && y >= centerColumn)
       {
             chessBoard(centerRow,centerColumn,x,y,ss);
       }
       else
       {
             chess[centerRow][centerColumn] = t;
             chessBoard(centerRow,centerColumn,centerRow,centerColumn,ss);
       }
       
}


int main()
{
      int Size;
      int x, y;
      while(cin >> Size && Size)
      {
            memset(chess, 0, sizeof(chess));
            cin >> x >> y;
            chessBoard(0,0,x,y,Size);     
            chess[x][y] = number = 1;        
            
            for(int i = 0 ; i < Size; i++)
            {
                  for(int j = 0 ; j < Size ; j++)
                  {
                        cout << chess[i][j]<< "\t";
                  }
                  cout << endl << endl;;
            }
      }
      
      
      return 0;
}